The present invention relates generally to axles for vehicles and more particularly to fabricated axles for vehicles.
Typical steer axle assemblies for vehicles include a forged I-beam axle, and a pair of steering knuckles pivotally attached to opposite ends of the axle by way of king pins. Although they are generally strong and reliable, such forged I-beam axles are limited in their shape, are relatively heavy, and require a relatively large amount of machining. All of this translates into increased manufacturing and payload costs.
In light of the foregoing, fabricated axles have been developed. Such axles are typically manufactured from sheets of steel that are cut and then welded together. Fabricated axles generally weigh less than forged I-beam axles. For example, a typical forged I-beam steering axle for use with the heavy-duty trucks weighs approximately one hundred ninety-five pounds, whereas an equivalent typical fabricated axle weighs approximately one hundred twenty-five pounds. In the case of commercial vehicles, including heavy-duty truck commercial vehicles, this translates into substantially increased payload capacity.
Another benefit of fabricated axles is that the material used (e.g., steel) can be spread around for more efficient distribution thereof. This can contribute to making the fabricated axle much lighter, and can even make it stiffer against both bending and torsion stresses. On top of all this, fabricated axles typically require less machining than forged I-beam axles. Accordingly, they are easier and less expensive to manufacture.
As implied above, fabricated axles are known in the art. An example of a fabricated axle is shown and described in U.S. Pat. No. 5,810,377, issued to Keeler et al., the disclosure of which is hereby incorporated herein by reference. The fabricated axle disclosed therein and incorporated herein by reference was a marked improvement over what was then the prior art and it is still useful for most purposes. However, it has now been recognized to have certain deficiencies. In particular, that fabricated axle does not utilize material efficiently, causing increased costs in manufacture and material waste. Furthermore, it fails to integrate several of the steering features that can be integrated in a fabricated axle for optimization of design, as demonstrated by the present invention. These and other deficiencies, many of which will be apparent to those skilled in the art, particularly after reading this description, have led to the development of the present invention.
Referring briefly to FIGS. 1-3, the main body part of the fabricated axle shown and described in U.S. Pat. No. 5,810,377 is illustrated. As shown, a plate 20 of material is used for the main body part of the material of the fabricated axle. A main body blank 22 is cut from plate 20 to form the main body of the fabricated axle. The remainder of plate 20 is waste and left unused. This waste material is identified by reference numeral 23 in FIG. 1. The main body blank 22 is then bent or folded along lines 24, 26 to form the main body of the fabricated axle. The main body blank forms a U-channel configuration at its central portion, as best shown in FIG. 3. As will be appreciated, the fabricated axle is also formed with additional sheets of metal welded to its main body. Reference can be made to U.S. Pat. No. 5,810,377 for further understanding of this construction.
As will be appreciated, a relatively large amount of material is wasted during construction of the fabricated axle shown and described in U.S. Pat. No. 5,810,377. This results in a considerable drawback to the extent that it becomes more expensive to manufacture that fabricated axle. Reasons for this inefficient use of material is that the main body part extends completely along the length of the steering axle such that it has an irregular shape, as shown in FIG. 1.
In light of the foregoing, it is desirable to provide for a fabricated vehicle axle that has substantially high material utilization.
It is also desirable to provide for a fabricated vehicle axle offering increased strength to bending and torsion stresses.
It is further desirable to provide for a fabricated vehicle axle that is less expensive to manufacture.
It is still further desirable to provide for a fabricated vehicle axle that integrates several of the steering system component functions.
These and other benefits of the preferred form of the invention will become apparent from the following description. It will be understood, however, that an apparatus could still appropriate the invention claimed herein without accomplishing each and every one of these benefits, including those gleaned from the following description. The appended claims, not the above listed benefits, define the subject matter of this invention. Any and all benefits are derived from the preferred form of the invention, not necessarily the invention in general.